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IndirectFlatPlateAbsorption v2

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Summary

Calculates indirect absorption corrections for a flat sample shape.

Properties

Name	Direction	Type	Default	Description
SampleWorkspace	Input	MatrixWorkspace	Mandatory	Sample workspace
SampleChemicalFormula	Input	string	Mandatory	Chemical formula for the sample
SampleDensityType	Input	string	Mass Density	Use of Mass density or Number density. Allowed values: [‘Mass Density’, ‘Number Density’]
SampleDensity	Input	number	0.1	Mass density (g/cm^3) or Number density (atoms/Angstrom^3)
SampleHeight	Input	number	1	Sample height
SampleWidth	Input	number	1	Sample width
SampleThickness	Input	number	0.5	Sample thickness
SampleAngle	Input	number	0	Sample angle
CanWorkspace	Input	MatrixWorkspace		Container workspace
UseCanCorrections	Input	boolean	False	Use can corrections in subtraction
CanChemicalFormula	Input	string		Chemical formula for the Container
CanDensityType	Input	string	Mass Density	Use of Mass density or Number density. Allowed values: [‘Mass Density’, ‘Number Density’]
CanDensity	Input	number	0.1	Mass density (g/cm^3) or Number density (atoms/Angstrom^3)
CanFrontThickness	Input	number	0.1	Can front thickness
CanBackThickness	Input	number	0.1	Can back thickness
CanScaleFactor	Input	number	1	Scale factor to multiply can data
BeamHeight	Input	number	1	Height of the beam (cm)
BeamWidth	Input	number	1	Width of the beam (cm)
NumberWavelengths	Input	long	10	Number of wavelengths for calculation
Events	Input	long	1000	Number of neutron events
OutputWorkspace	Output	MatrixWorkspace	Mandatory	The output corrected workspace
CorrectionsWorkspace	Output	WorkspaceGroup		The workspace group to save correction factors

Description

Calculates and applies corrections for scattering abs absorption in a flat plate sample for a run on an indirect inelastic instrument, optionally allowing for the subtraction or corrections of the container. Uses MonteCarloAbsorption to calculate the corrections.

The correction factor workspace is a workspace group containing the correction factors in the Paalman and Pings format, note that only \({A_{s,s}}\) and \(A_{c,c}\) factors are calculated by this algorithm.

Workflow

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Usage

Note

To run these usage examples please first download the usage data, and add these to your path. In Mantid this is done using Manage User Directories.

Example - Sample corrections for IRIS:

red_ws = LoadNexusProcessed(Filename='irs26176_graphite002_red.nxs')
can_ws = LoadNexusProcessed(Filename='irs26173_graphite002_red.nxs')

corrected, fact = IndirectFlatPlateAbsorption(SampleWorkspace=red_ws,
                                              SampleChemicalFormula='H2-O',
                                              CanWorkspace=can_ws,
                                              CanScaleFactor=0.8,
                                              SampleHeight=1,
                                              SampleWidth=1,
                                              SampleThickness=1,
                                              Events=100,
                                              UseCanCorrections=False)

ass = fact[0]

print ('Corrected workspace is intensity against %s'
      % (corrected.getAxis(0).getUnit().caption()))

print ('Ass workspace is %s against %s'
      % (ass.YUnitLabel(), ass.getAxis(0).getUnit().caption()))

Output:

Corrected workspace is intensity against Energy transfer
Ass workspace is Attenuation factor against Wavelength

Example - Sample and container corrections for IRIS:

red_ws = LoadNexusProcessed(Filename='irs26176_graphite002_red.nxs')
can_ws = LoadNexusProcessed(Filename='irs26173_graphite002_red.nxs')

corrected, fact = IndirectFlatPlateAbsorption(SampleWorkspace=red_ws,
                                              SampleChemicalFormula='H2-O',
                                              CanWorkspace=can_ws,
                                              CanChemicalFormula='V',
                                              CanScaleFactor=0.8,
                                              SampleHeight=1,
                                              SampleWidth=1,
                                              SampleThickness=1,
                                              Events=100,
                                              UseCanCorrections=True)

ass = fact[0]
acc = fact[1]

print ('Corrected workspace is intensity against %s'
      % (corrected.getAxis(0).getUnit().caption()))

print ('Ass workspace is %s against %s'
      % (ass.YUnitLabel(), ass.getAxis(0).getUnit().caption()))

print ('Acc workspace is %s against %s'
      % (acc.YUnitLabel(), acc.getAxis(0).getUnit().caption()))

Output:

Corrected workspace is intensity against Energy transfer
Ass workspace is Attenuation factor against Wavelength
Acc workspace is Attenuation factor against Wavelength

Categories: AlgorithmIndex | Workflow\Inelastic | CorrectionFunctions\AbsorptionCorrections | Workflow\MIDAS

Source

Python: IndirectFlatPlateAbsorption2.py